First let’s recap, what is app-ads.txt
App-ads.txt is a specification by the IAB to help fight advertising fraud. It works by a publishing app (they make money from the ads) linking their developer site with a txt file which has their advertising publisher IDs. Thus a buyer of the publisher’s ads can lookup the ID they’ve been buying from to verify that they’re buying from the real publisher.
IAB App-Ads.txt Standard
The two screenshots are from the 2019 IAB app-ads.tx final specification. The app store’s were supposed to maintain a <meta> in the header which contained the developer URL. In the classic example, screenshot from the PDF above, Angry Bird’s store page would show <meta name=appstore:developer_url content="https://rovio.com" />.
You can still see this today on Google’s Playstore pages:
Though the IAB app-ads.txt was never as well supported as the original ads.txt.
Apple’s developer_url and sellerUrl no longer available
This probably happened awhile ago, as I do not regularly check, but now when checking for corresponding “developer_url” on various apps on Apple App Store pages I can no longer see any that have “appstore:developer_url”.
Similarly, the Apple iTunes Lookup API also no longer includes the sellerUrl which used to also work as an easy way to get the developer’s url.
It seems Apple’s policy was to hide various programmatic ways of getting an app’s web URL.
Options? Scrape the page, the URL is still there, just not in the canonical place
So there is a fallback, but I think this signal’s an official end to support of the app-ads.txt specification by Apple.
Bigger implications? Apple’s monopoly position in mobile app ads is a bit stronger
Apple continues to push into advertising space, and it’s own advertising service has never needed to support app-ads.txt given they are the monopoly on the app store. Removing the app-ads.txt support forces any other smaller ad companies attempting to sell ads on the open market to compete with one less tool to fight advertising fraud.
Update: Oops, maybe Apple NEVER officially supported IAB specs?
Two people questioned whether Apple had EVER supported the IAB specs and it looks like Apple maybe never did; based on my checks using the Wayback machine. I checked January 2019 and July 2019 but neither had the appstore:developer_url.
This is a bit confusing given the screenshots above from March 2019’s IAB specs, but my guess now was that those were put out without the OK from Apple? As someone who’s maintained a personal app-ads.txt crawler since then, I guess it was just easier to use the iTunes API anyways rather than crawling HTML, so the real change here is the loss of sellerUrl which was the easiest way to get the canonical website of an app’s owner.
It’s not directly Apple trying to maintain their advertising and data monopoly over their phones, but it indirectly is just another banana peel in the road for their competitors.